JP2014094843A - Molten glass transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely control generation of bubbles in molten glass circulating in a noble metal pipe by coating the outer peripheral surface of the noble metal pipe with the molten glass simply and surely.SOLUTION: In a molten glass transfer device including a noble metal pipe 15 for circulating molten glass G through the internal space S1, and a refractory 16 for forming a filling space S2 of the molten glass G between itself and the outer peripheral surface of the noble metal pipe 15 by enclosing the outer peripheral surface of the noble metal pipe 15, the noble metal pipe 15 communicates with the filling space S2, and has a supply hole 20 for supplying the molten glass G circulating through the internal space S1 into the filling space S2.

Description

  The present invention relates to a molten glass transfer device having a noble metal tube through which molten glass flows.

  In general, when glass articles such as thin glass are continuously formed, for example, after the glass raw material is heated and melted in the molten glass in the glass melting chamber, the molten glass undergoes various processes such as a clarification process and a stirring process. Supplied to the compact. Under the present circumstances, the molten glass melt | dissolved in the glass melting chamber is transferred to a molded object by distribute | circulating a predetermined | prescribed flow path (for example, refer patent document 1).

  As a flow path for circulating molten glass, for example, as disclosed in Patent Document 2, a noble metal tube made of platinum, a platinum alloy or the like is usually used from the viewpoint of ensuring heat resistance and oxidation resistance. It is.

  Here, according to the document, when molten glass is circulated in a noble metal tube, oxygen bubbles are generated in the molten glass in the process. Since the molten glass that circulates in the precious metal tube is used to form glass parts that are products, if oxygen bubbles are generated in the molten glass, oxygen bubbles are generated in the glass parts that are finally formed. There may be a problem that the resulting defects are formed.

  In particular, in the case of glass substrates for flat panel displays such as liquid crystal display panels, high product quality is required, so when defects due to oxygen bubbles are formed, the required quality is not met. It is easy to invite a situation that must be handled as a defective product.

  The reason why oxygen bubbles are formed in the molten glass as described above is described in Patent Document 2 as follows. That is, depending on the external environment of the noble metal tube (for example, when the hydrogen partial pressure in the external environment is low), hydrogen derived from moisture in the molten glass permeates through the noble metal tube and is easily released out of the noble metal tube. As a result, the oxygen concentration derived from the moisture in the molten glass flowing through the noble metal tube is increased, and oxygen bubbles that cause defects are generated.

  Therefore, in order to maintain the high quality of the glass article, it is indispensable to take measures to reduce oxygen bubbles in the molten glass. Therefore, in Patent Document 2, a solid glass such as cullet, crushed glass, or glass powder is filled between a noble metal pipe and a refractory (heat insulating material) surrounding the outer peripheral surface of the noble metal pipe, and then the noble metal pipe is used. The outer peripheral surface of the glass is melted so as to get wet.

  If it does in this way, the situation where the hydrogen derived from the water in the molten glass which distribute | circulates the inside of a noble metal pipe permeate | transmits outside by the molten glass which coat | covers the outer peripheral surface of a noble metal pipe will be suppressed. Therefore, the respective concentrations of hydrogen and oxygen derived from moisture in the molten glass flowing through the interior of the noble metal tube are properly maintained, and oxygen bubbles are not easily formed.

JP 2007-145668 A JP 2004-523449 A

  However, even if the method disclosed in Patent Document 2 is adopted, the following problems remain.

  First, since the solid glass must be supplied to the space between the noble metal tube and the refractory, it is difficult to uniformly fill the space between the noble metal tube and the refractory and the efficiency is poor. In particular, such a problem becomes more prominent as the shape of the noble metal tube becomes complicated, for example, when the noble metal tube is bent halfway.

  Secondly, since the space between the noble metal tube and the refractory is high temperature, it is difficult to visually check the filling amount of the solid glass, and the filling amount becomes inappropriate. There is also a possibility that a situation in which the outer peripheral surface of the pipe cannot be effectively covered may occur.

  In view of the above circumstances, it is an object of the present invention to reliably suppress the generation of bubbles in the molten glass flowing through the noble metal tube by simply and reliably coating the outer peripheral surface of the noble metal tube with the molten glass. And

  The present invention was devised to solve the above-described problems. The present invention provides a precious metal tube having an internal space for circulating molten glass, and an outer peripheral surface of the precious metal tube that surrounds the outer peripheral surface of the precious metal tube. A molten glass transfer device comprising a refractory forming a filling space, wherein the noble metal pipe has a supply hole that communicates with the filling space and supplies molten glass flowing through the inner space to the filling space. It is characterized by doing.

  According to such a structure, the molten glass which distribute | circulates the internal space of a noble metal pipe | tube is automatically supplied to a filling space through a supply hole. Therefore, the outer peripheral surface of the noble metal tube can be easily and easily covered with the molten glass supplied to the filling space through the supply hole. Therefore, the situation where hydrogen permeates from the inner space of the noble metal tube is reliably suppressed by the molten glass covering the outer peripheral surface of the noble metal tube, and the generation of bubbles in the molten glass flowing through the inner space of the noble metal tube is possible. Can be reduced. Also, at this time, even if the molten glass in the filling space soaks into the joints of the refractory (for example, refractory bricks) or the refractory itself, and the liquid level of the molten glass in the filling space falls, Due to the pressure balance of the filling space, the molten glass is automatically supplied from the inner space of the noble metal tube to the filling space through the supply hole, and the noble metal tube can always be covered with the molten glass.

  In the above configuration, the noble metal pipe has a vertical pipe portion extending in the vertical direction, and the supply hole is provided in the vertical pipe portion at a height position near the liquid surface of the molten glass flowing in the vertical pipe portion. It may be done.

  If it does in this way, molten glass will be supplied to filling space from the height substantially the same as the height of the liquid level of molten glass in a vertical tube part. And the molten glass supplied to the filling space moves below the vertical tube portion by its own weight. Therefore, the outer peripheral surface of the vertical tube portion can be reliably covered in the area where the molten glass is circulating in the vertical tube portion.

  In this case, it is preferable that the opening on the inner space side of the supply hole is a long hole extending in the vertical direction.

  That is, the height of the liquid surface of the molten glass in the vertical tube portion may fluctuate up and down due to pressure loss or the like, but if the opening on the vertical tube portion side of the supply hole is a long hole extending in the vertical direction, the liquid level Surface variations can be accommodated within the supply holes. Therefore, even if the liquid level of the molten glass fluctuates, the molten glass can be reliably supplied to the filling space through the supply holes.

  Said structure WHEREIN: The said noble metal pipe | tube may have a horizontal pipe part extended in a substantially horizontal direction, and the said supply hole may be provided near the top part of the outer periphery of the said horizontal pipe part.

  If it does in this way, the molten glass supplied to the filling space from the supply hole of the horizontal pipe part will move toward the bottom part of the horizontal pipe part so as to cover the periphery of the horizontal pipe part by its own weight. Therefore, the outer peripheral surface of the horizontal tube portion can be reliably covered in the area where the molten glass is circulating in the horizontal tube portion.

  Said structure WHEREIN: It is preferable that the said supply hole has the bending part by which the flow path was bent before reaching the said filling space.

  In this way, the flow path of the supply hole up to the filling space becomes complicated. Therefore, it is possible to suppress the molten glass supplied to the filling space through the supply hole and coming into contact with the refractory from flowing back into the inner space of the noble metal tube through the supply hole again.

Said structure WHEREIN: It is preferable that the opening area of the said internal space side of the said supply hole is 150-2830 mm < ² >.

  If it does in this way, the molten glass supplied to filling space via a supply hole can be restrained to an appropriate quantity.

  As described above, according to the present invention, a part of the molten glass flowing through the inner space of the noble metal pipe is automatically supplied to the filling space through the supply hole provided in the noble metal pipe. Therefore, the outer peripheral surface of the noble metal tube can be easily and reliably covered with the molten glass, and it is possible to reliably suppress the generation of bubbles in the molten glass flowing through the inner space of the noble metal tube.

It is a figure which shows the plate glass manufacturing apparatus provided with the molten glass transfer apparatus which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of the stirring tank vicinity of the molten glass transfer apparatus which concerns on this embodiment. It is the longitudinal cross-sectional view which expanded the supply hole periphery of FIG. It is a longitudinal cross-sectional view of the flow-path connection part which connects the stirring tank and pot of the molten glass transfer apparatus which concerns on this embodiment. It is SS sectional drawing of FIG. It is a longitudinal cross-sectional view which shows the modification of the supply hole of the molten glass transfer apparatus which concerns on this embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration of a plate glass manufacturing apparatus including a molten glass transfer device according to an embodiment of the present invention. This plate glass manufacturing apparatus is a volume part that mainly adjusts the viscosity of the clarification chamber 2, the stirring tank 4 having the stirring blade 3, and the molten glass G in order from the upstream side to the downstream side of the melting chamber 1 disposed at the upstream end. The pot 5 is provided.

  In the lower part of the pot 5, there is formed a flow passage area restricting portion 6 whose diameter gradually decreases as it moves downward. A small diameter portion 7 is connected to the downstream end of the flow path area restricting portion 6. A large-diameter portion 9 having a bent portion 8 is provided on the downstream side of the small-diameter portion 7. A molded body 11 communicates with the downstream end portion 10 of the large-diameter portion 9, and the molten glass G is molded into a plate shape in the molded body 11.

  The dissolution chamber 1 and the clarification chamber 2, the clarification chamber 2 and the agitation tank 4, and the agitation tank 4 and the pot 5 are connected by flow path connecting parts 12, 13, and 14, respectively.

  In this embodiment, the molded body 11 has a substantially wedge-shaped cross section and executes the overflow downdraw method, and is configured to mold the molten glass G into a plate shape as follows. First, molten glass G is continuously supplied to an overflow groove (not shown) formed in the upper part of the molded body 11, and the molten glass G overflows from the overflow groove and flows down along the side wall surfaces on both sides of the molded body 11. . And the molten glass G which flowed down is united by the lower top part of the molded object 11, respectively, and it is set as a sheet-like form. Thereafter, when the plate-like glass molded product is solidified, it is pulled out downward while being held by a pulling roller, thereby obtaining a plate glass to finally become a product. In addition, the plate glass manufactured in this way is 0.05-1.0 mm in thickness, for example, Flat panel displays, such as a liquid crystal display and an organic EL display, Organic EL lighting, Substrates, such as a solar cell, and a protective cover Used for

  In the above configuration, the flow path from the melting chamber 1 to the molded body 11 (the clarification chamber 2, the stirring tank 4, the pot 5, the flow path connecting portions 12, 13, 14, etc.) serves as a molten glass transfer device. . In this plate glass manufacturing apparatus, the flow path for supplying the molten glass G to the compact 11 is assumed to be composed of a noble metal tube. Below, the molten glass transfer apparatus integrated in the plate glass manufacturing apparatus is explained in full detail.

  The molten glass transfer device will be described by taking the periphery of the stirring vessel 4 as an example. As shown in FIG. 2, the noble metal tube 15 having an internal space S1 through which the molten glass G supplied to the molded body 11 circulates, and the noble metal tube. And a refractory 16 that forms a filling space S2 of molten glass G between the outer peripheral surface of the noble metal tube 15 and the outer peripheral surface of the noble metal tube 15.

  Examples of the noble metal pipe 15 include a platinum pipe or a platinum alloy pipe, and examples of the refractory 16 include a refractory brick.

  In the vicinity of the stirring tank 4, the noble metal pipe 15 has horizontal pipe parts 17 and 18 through which the molten glass G flows substantially horizontally, corresponding to the flow path connecting parts 13 and 14, and the part corresponding to the stirring tank 4. Is the vertical tube portion 19 through which the molten glass G flows in the vertical direction. The upstream side horizontal pipe part 17 is connected above the vertical pipe part 19, and the downstream side horizontal pipe part 18 is connected below the vertical pipe part 19. The molten glass G flowing in the upstream side horizontal tube portion 17 flows into the vertical tube portion 19 from the upper side and moves downward in the vertical tube portion 19, and downstream on the lower side of the vertical tube portion 19. It flows out into the side tube portion 18 on the side.

  The vertical pipe portion 19 is provided with a supply hole 20 that communicates with the filling space S2 and supplies molten glass G flowing through the internal space S1 of the vertical pipe portion 19 to the filling space S2. In FIG. 2, the surface of the periphery of the supply hole 20 is shown not as a cross section by leaving a part of the vertical pipe portion 19. Further, in the figure, the agitating blade 3 is not shown.

  A plurality of supply holes 20 are provided at intervals in the circumferential direction of the vertical tube portion 19 at a height position near the liquid level L of the molten glass G flowing through the internal space S1 of the vertical tube portion 19. The supply hole 20 may be provided only at one place in the circumferential direction of the vertical pipe portion 19.

  Specifically, as shown in FIG. 3, the supply hole 20 includes an opening 21 provided on the side surface of the vertical pipe portion 19 and a cover 22 that covers the opening 21 from the side. Only the lower side of the cover 22 is open. The molten glass G flowing through the internal space S1 of the vertical pipe portion 19 enters the cover 22 through the opening 21 as shown by an arrow A in the figure, and is then supplied from the lower end of the cover 22 to the filling space S2. . That is, in this embodiment, the supply hole 20 has a bent portion where the flow path is bent downward.

  The opening 21 is constituted by a long hole extending in the vertical direction, and the liquid level L of the molten glass G flowing through the internal space S1 of the vertical tube portion 19 is located within the range of the opening 21. Of course, the liquid level L of the molten glass G may be located above the upper end of the opening 21. In addition, the position of the opening 21 is not based on the height of the actual liquid level L of the molten glass G flowing through the internal space S1 of the vertical tube part 19, but the liquid level of the molten glass G in the melting chamber 1 The height may be determined based on the height. This is because the liquid surface of the molten glass G does not become higher on the downstream side than the liquid surface of the molten glass G in the melting chamber 1.

The opening area of the opening 21 is, for example, 150 to 900 mm ² . Specifically, the size of the opening 21 formed of a long hole is, for example, 5 mm to 15 mm in the width direction dimension a and 30 mm to 60 mm in the vertical dimension b. In addition, a and b shall follow FIG.

  According to the configuration as described above, the molten glass G flowing through the internal space S1 of the vertical tube portion 19 is automatically transferred to the filling space S2 through the supply hole 20 partly composed of the opening 21 and the cover 22. To be supplied. At this time, the molten glass G is supplied to the filling space S <b> 2 from a height substantially the same as the height of the liquid level L of the molten glass G in the internal space S <b> 1 of the vertical tube portion 19. Therefore, the outer peripheral surface of the vertical pipe part 19 can be covered easily and reliably in the area where the molten glass G is circulating in the internal space S1 of the vertical pipe part 19. Therefore, the situation that hydrogen permeates from the internal space S1 of the vertical tube portion 19 to the filling space S2 by the molten glass G covering the outer peripheral surface of the vertical tube portion 19 is reliably suppressed, and the internal space S1 of the vertical tube portion 19 is suppressed. The generation of bubbles in the molten glass G flowing through can be reduced as much as possible.

  Further, it is conceivable that the molten glass G in the filling space S2 penetrates into the joints of the refractory 16 or the refractory 16 itself, and the liquid level L of the molten glass G in the filling space S2 is lowered. A pressure difference is generated between the internal space S1 and the filling space S2 of the pipe part 19, and the molten glass G is automatically supplied from the internal space S1 to the filling space S2.

  Furthermore, since the supply hole 20 has a bent portion up to the filling space S2, the shape of the flow path becomes complicated as compared with the case where the supply hole 20 is configured by only the opening 21. Therefore, it is difficult for the molten glass G once supplied to the filling space S <b> 2 to flow back into the vertical tube portion 19 through the supply hole 20. Since the molten glass G is in contact with the refractory 16 in the filling space S2, in order to maintain the cleanliness of the molten glass G in the internal space S1 of the vertical tube portion 19, it is supplied to the filling space S2 as described above. A configuration in which the molten glass G thus made is difficult to flow back into the longitudinal tube portion 19 is desirable. From such a viewpoint, the lower end of the cover 22 is preferably positioned below the lower end of the opening 21. That is, it is preferable that the entire opening 21 is covered with the cover 22 without the opening 21 protruding from the cover 22 in a side view.

  Moreover, since the opening part 21 is comprised by the elongate hole extended in an up-down direction, even if the height of the liquid level L of the molten glass G which distribute | circulates the internal space S1 of the vertical pipe part 19 changes with pressure loss etc. The variation of the liquid level L of the molten glass G can be dealt with within the range of the opening 21. Therefore, even if the height of the liquid level L of the molten glass G varies, the molten glass G can be reliably supplied to the filling space S <b> 2 through the supply hole 20.

  As shown in FIGS. 4 and 5, in this embodiment, the molten glass G that circulates in the internal space S <b> 1 of the horizontal tube portion 18 also in the horizontal tube portion 18 of the noble metal tube 15 corresponding to the flow path connecting portion 14. Is provided in the filling space S2.

  A plurality of supply holes 23 are provided at a position near the top of the horizontal tube portion 18 in the circumferential direction with an interval in the axial direction of the horizontal tube portion 18. The supply hole 23 may be provided only at one place in the axial direction of the horizontal tube portion 18.

  Specifically, the supply hole 23 includes an opening 24 and a cover 25, similarly to the supply hole 20 of the vertical pipe portion 19 described above. The cover 25 is open only on the upstream side in the axial direction of the horizontal tube portion 18. As shown in FIG. 4, the molten glass G flowing through the internal space S <b> 1 of the horizontal tube portion 18 enters the cover 25 through the opening 24 according to the arrow B in the figure, and then is filled from the upstream end of the cover 25. Supplied to S2. Then, as shown in FIG. 5, the molten glass G supplied from the supply hole 23 to the filling space S <b> 2 passes the filling space S <b> 2 along the outer peripheral surface of the horizontal pipe portion 18 according to the arrow C in the drawing. Move to the bottom side of the. Therefore, the entire outer peripheral surface of the horizontal tube portion 18 can be covered with the molten glass G. Note that the cover 25 may be opened only on the downstream side in the axial direction of the horizontal tube portion 18.

The opening area of the opening 24 of the horizontal tube portion 18 is, for example, 300 to 2830 mm ² . When providing the supply hole 23 in the horizontal pipe part 18, the opening part 24 does not need to be a long hole, A round hole may be sufficient. When the opening 24 has a round hole shape, the diameter of the opening 24 is preferably 20 to 60 mm, for example.

  Here, although not shown, in this embodiment, the pot 5 also has a molten glass filling space between the noble metal tube and the refractory. Among these, the noble metal pipe corresponding to the pot 5 is provided with a supply hole similar to the vertical pipe portion 19 described in the stirring tank 4. Note that a filling space may also be provided in the small diameter pipe 7.

  Further, when noble metal is used for the flow path connecting portion 12 and the clarification chamber 2, a filling space and a supply hole are similarly formed in the flow path connection portion 12 and the clarification chamber 2, and filling is performed from the inner space of the noble metal pipe through the supply hole. Molten glass may be supplied to the space, and the outer peripheral surface of the noble metal tube may be covered with molten glass.

  Further, in this embodiment, as shown in FIG. 2, electrodes 26 to 29 are provided at a plurality of locations on the outer peripheral surface of the noble metal tube 15, and the noble metal tube 15 is heated by energizing the electrodes 26 to 29. However, the molten glass G is circulated inside the noble metal tube 15. Each of the electrodes 26 to 29 is formed in a bowl shape on the outer peripheral surface of the noble metal tube 15.

  As shown in FIG. 2, a molten glass discharge pipe 30 for discharging the molten glass G existing in the internal space S <b> 1 is provided at the bottom of the stirring tank 4. As a result, the molten glass G present in the internal space S1 can be appropriately discharged to replenish the internal space S1 with new molten glass G. Although not shown, the molten glass discharge pipe 30 is configured to be able to open and close the flow path as appropriate, and the flow path is closed except when the molten glass G is discharged from the molten glass discharge pipe 30. Yes.

  As shown in FIG. 4, the flow path coupling portion 14 is provided with a gas discharge pipe 31 for removing the bubbles X contained in the molten glass G in the filling space S2. Thereby, it becomes possible to remove the bubbles contained in the molten glass G present in the filling space S2. In addition, although not shown in figure, the gas exhaust pipe 31 becomes a structure which can open and close a flow path suitably, and it will be in the state where the flow path was closed except when discharging the gas which comprises the bubble X from the gas exhaust pipe 31. ing.

  In addition, this invention is not limited to said embodiment, It can implement with a various form. For example, in the above-described embodiment, the case where the molten glass transfer device is incorporated in a manufacturing apparatus that manufactures plate glass by the overflow downdraw method has been described. However, manufacturing of manufacturing plate glass by another downdraw method such as the slot downdraw method is described. It may be incorporated into the device.

  In the above-described embodiment, the case where the supply hole is provided near the liquid surface of the molten glass in the vertical tube portion has been described. However, instead of or in combination, the supply hole is provided at an intermediate position in the vertical direction of the vertical tube portion. May be provided. Similarly, the case where the supply hole is provided in the vicinity of the top in the circumferential direction of the horizontal tube portion has been described, but instead of or in combination, the supply hole is provided at other circumferential positions such as the side and bottom of the horizontal tube portion. May be provided. The number and arrangement positions of the supply holes can be changed as appropriate.

  In the above embodiment, a case has been described in which the supply hole is configured by an opening and a cover, and a part of the supply hole is configured by the outer peripheral surface of the noble metal tube. However, as illustrated in FIG. A flow path can be formed in the opening 21 of the vertical pipe portion 19 independently of the vertical pipe portion 19 and a pipe 32 bent in a substantially L shape may be connected to form the supply hole 20. In this case, the opening (exit) on the filling space S <b> 2 side of the supply hole 20 can be provided away from the outer peripheral surface of the vertical pipe portion 19. The configuration of the supply hole having such a pipe can be similarly applied to a horizontal pipe portion which is a noble metal pipe.

DESCRIPTION OF SYMBOLS 1 Dissolution room 2 Clarification room 3 Stirring blade 4 Stirrer tank 5 Pot 6 Flow path area throttle part 7 Small diameter part 8 Curved part 9 Large diameter pipe 10 Downstream end part 11 Molded body 12-14 Channel connection part 15 Precious metal pipe 16 Refractory 17, 18 Horizontal tube portion 19 Vertical tube portion 20 Supply hole 21 Opening portion 22 Cover 23 Supply hole 24 Opening portion 25 Cover 26 to 29 Electrode 30 Molten glass discharge tube 31 Gas discharge tube

Claims (6)

Molten glass transport comprising a noble metal tube having an internal space for circulating molten glass and a refractory material surrounding the outer peripheral surface of the noble metal tube and forming a molten glass filling space between the outer peripheral surface of the noble metal tube A device,
The molten glass transfer device, wherein the noble metal pipe has a supply hole that communicates with the filling space and supplies molten glass flowing through the internal space to the filling space.   The noble metal pipe has a vertical pipe portion extending in the vertical direction, and the supply hole is provided in the vertical pipe portion at a height position near the liquid surface of the molten glass flowing in the vertical pipe portion. The molten glass transfer apparatus according to claim 1.   The molten glass transfer device according to claim 2, wherein the opening on the inner space side of the supply hole is a long hole extending in the vertical direction.   The said noble metal pipe | tube has a horizontal pipe part extended in a substantially horizontal direction, and the said supply hole is provided in the top part vicinity of the circumferential direction of the said horizontal pipe part. The molten glass transfer apparatus according to item 1.   The molten glass transfer device according to any one of claims 1 to 4, wherein the supply hole has a bent portion in which a flow path is bent before reaching the filling space. The molten glass transfer device according to claim 1, wherein an opening area of the supply hole on the inner space side is 150 to 2830 mm ² .

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